Hot water is an important luxury that we often take for granted. It's used for tasks such as washing vegetables in the kitchen and cleaning our hands with soap.
But what do you do when the water coming from the faucet is cold? Or you have to wait for your traditional water heater to heat up, resulting in wasted cold water going down the drain?
Large houses may not receive enough hot water from a traditional storage-type water heater if it is too far from the kitchen and bathrooms. Or, you may not have a water heater in a garage, greenhouse, or outhouse.
Fortunately, there are both tanked-type and tankless under sink water heaters that are easy to install and surprisingly affordable. They come in a variety of sizes and have stealthy designs that blend seamlessly into modern bathroom aesthetics.
In this article, we will delve into the best under sink water heaters and provide all the information you need to know before purchasing one.
Top Under Sink Water Heaters in 2023
Hot water is essential in modern homes and waiting for your water to warm up is a waste of energy as well as time.
- Continuous flow at 1.5GPM
- Minimalist design
- Exceptionally powerful
- Saves energy bills
- 4-gallon capacity
- Space-saving design
- Built to last
- Built for easy mounting
- 6-year warranty
- Well-insulated energy saving design
- 2.5 gallons capacity
- Freeze zone safety feature
- Faster heating
- Flow rate of 1.5 GPM
- LCD display
- Easy installation
- 2.5-gallon capacity
- Anti-freeze mode (safety feature)
- Reaches temperature of 167°F (so hot!)
- 2.5-gallon tank
Here are the top-rated under-sink water heaters of 2023 to give you an instant hot water hit.
1. EcoSmart ECO 11 – Best For Continuous Flow
The EcoSmart ECO 11 is a tankless under sink water heater known for its efficiency and lifetime warranty. However, it does come with a premium price tag.
|Compatibility||Requires 125 Amperes of power|
|Energy Efficiency||99.8% efficient|
|Flow Rate||1.5 GPM when heating water by 60°F|
|Price||Premium price tag|
The EcoSmart ECO 11 is a tankless water heater that's designed to fit seamlessly into bathroom and kitchen design. It has a digital display, a swivel dial on the front, and EcoSmart branding, which gives it a slightly cluttered appearance. Despite this, the company has made efforts to create a powerful and efficient water heater. The slim, chic design of the EcoSmart ECO 11 allows it to fit easily around any sink in your home.
However, the EcoSmart ECO 11 requires 125 Amperes of power, which may not be compatible with the power supply in most homes. It's important to have a qualified electrician install and wire this unit to prevent the risk of a fire hazard in your home.
The EcoSmart ECO 11 is highly energy efficient, running at 99.8%. It can provide a continuous flow of hot water and has a flow rate of 1.5 GPM when heating water by 60°F. This means that, if your water starts out at 45°F, the EcoSmart ECO 11 can provide water heated to 105°F in a continuous flow at 1.5 GPM.
2. Bosch ES4 Tronic 3000T – Best Choice For A Bigger Capacity
Bosch offers mini-tank water heaters in 2.5, 4, and 7-gallon capacities. For the purpose of this review, we will focus on the Bosch ES4 Tronic 3000T model, which offers a balance of size and capacity.
|Water tank||Glass-lined, insulated with CFC-free foam|
|Water temperature||Can be adjusted with a front dial, ranging from minimum to maximum|
|Reheat time||30 minutes for 4 gallons of water at 90°F|
|Mounting options||Floor or wall mounting|
|Power cord||36 inches|
The Bosch ES4 Tronic 3000T has a solid plastic chassis that houses the glass-lined water tank, which is insulated with CFC-free foam. This demonstrates Bosch's commitment to being environmentally friendly. The 4-gallon model of the Bosch ES4 Tronic 3000T is suitable for either floor or wall mounting and comes with brackets for installation. It can be easily installed with a simple toolkit and is powered by a 36-inch power cord.
The front dial of the Bosch ES4 Tronic 3000T allows you to choose the water temperature, ranging from minimum to maximum, with an “ideal” setting labeled on the dial. However, the absence of a digital display means that you have to estimate the temperature. When 4 gallons of water are used, it may take up to 30 minutes to reheat the water at 90°F. If you prefer your water to be superheated, it may take longer to reheat.
3. Stiebel Eltron SHC 2.5 – Best For Quick Reheating
The Stiebel Eltron SHC 2.5 has a 2.5-gallon capacity, providing instant hot water without taking up much space.
|Temperature Range||86°F – 140°F|
|Internal tank material||Glass-lined steel|
|Reheat time||Fewer than 20 minutes|
The Stiebel Eltron SHC 2.5 has a stylish, flat-backed water tank that's built for easy wall mounting. It has a premium white plastic chassis with a clean, minimalistic design and just the Stiebel logo on the front. However, the control dial is placed on top, which can limit installation as you need to leave space above the unit to reach it.
The internal steel tank is glass-lined, making it durable and it's also insulated to keep water warmer for longer. The Stiebel Eltron SHC 2.5 comes with a six-year warranty for added reassurance about its quality.
Installation of Stiebel Eltron SHC 2.5 is easy and includes everything you need, except for common tools. The unit comes with brackets and screws for wall mounting and can be plumbed in without professional input.
Once installed, the Stiebel Eltron SHC 2.5 is ready to use. However, it has a smaller capacity and a reheat time of fewer than 20 minutes. Its 2.5-gallon capacity will only last for a minute at common faucet flow rates, which may not be enough time to do the dishes.
4. Camplux ME25 Mini Tank Electric Water Heater – Best Tank On A Budget
The Camplux ME25 tank is compact, making it easy to fit in small spaces where you need hot water quickly.
|Temperature Range||68°F -140°F|
|Material||Steel and glass-lined for durability|
|Recovery rate||6.8 GPH at 90°F|
|Reheat time||20-30 minutes at highest setting|
|Self-installation||Possible, but voids warranty|
The Camplux ME25 is a classic white, well-insulated water heater tank made of steel and glass-lined for added durability. Its 43” power cord is longer than what other manufacturers typically include, giving you more flexibility with placement.
While self-installation is possible for those with a handy streak, keep in mind that doing so will void the warranty. It's worth considering hiring professionals, as the T/P valve requires assembly and may pose some risks if attempting to install it yourself.
Once installed, the Camplux ME25 is easy to use with a front-facing dial that allows you to adjust the water temperature between 60°F and 140°F. While it doesn't have a digital display, it does mark 125°F on the sliding scale to help you gauge temperature.
With a capacity of 2.5 gallons, the Camplux ME25 has a recovery rate of 6.8 GPH at 90°F. This means it will take just over 20 minutes for the water to return to that temperature after use. At the highest setting of 125°F, it will take closer to 30 minutes to reheat. Keep this in mind if you plan on leaving the faucet running for an extended period of time.
5. ECOTOUCH ECO55 – Best Tankless Heater On A Budget
The ECOTOUCH ECO55 is a great space-saver that provides a continuous supply of hot water from your faucet. Its stylish design and energy efficiency make it stand out.
|Temperature Range||86°F – 140°F|
|Flow rate||Up to 1.5 GPM at 116°F, flow rate may be affected at higher temperatures|
|Installation||Professional installation recommended|
The ECOTOUCH ECO55 is built for durability, featuring a thermal water chamber kept separate from the electronics, and the chic black design screams of modernity. All metal components are contained within the unit, and the external screen feels solid to the touch. This is a relief as flimsy touchscreens are a bane of modern technology.
ECOTOUCH recommends professional installation, but the unit comes with everything needed, including brackets and cables, and is compatible with common ½” piping. It can be installed by an experienced handyman with no specialty plumbing skills.
The ECOTOUCH ECO55 heats water quickly and effectively up to 116°F in a continuous flow, although the flow rate may be affected at higher temperatures. At 116°F, the flow rate is around 1.5 GPM, slightly lower than the average faucet.
The ECOTOUCH ECO55 is energy efficient, with power automatically adjusting based on the required temperature and flow rate. When the faucet is turned on full, the ECOTOUCH ECO55 increases power to keep up. The LCD display is great for targeting precise water temperature, with accuracy within +/- 1°.
6. Eccotemp EM-2.5 – Best Compact Water Tank
The Eccotemp EM-2.5 gallon under sink water heater has a basic design of blue and white. It doesn't stand out in terms of aesthetics compared to other minimalistic and stylish water heaters. The power and heat indicators, which light up, also seem unnecessary.
|Temperature Range||86°F – 140°F|
|Dimensions||15” x 13.5”|
|Recovery rate||20-45 minutes, depending on temperature|
|Temperature Control||Front-facing dial with “off” to “max” range|
|Energy efficiency||Over 99%|
The Eccotemp EM-2.5 is a compact unit that measures 15” x 13.5”, making it ideal for under-sink cabinets and other small spaces. Installation is easy and doesn't require plumbing expertise. Simply attach the hoses to the input for cold water and the output for hot water, then connect it to your faucet. You'll need to purchase the ½” pipes separately, but all other connectors and brackets are included.
The temperature of the Eccotemp EM-2.5 is controlled with a front-facing dial, but it only offers a range of “off” to “max,” so you'll need to do some guesswork to get the desired output. It has a high output of 150 pounds per square inch (psi) and should not limit the flow rate of even the most powerful faucets. However, with a 2.5-gallon capacity, you may run out of hot water at such a high psi. The recovery rate of 20-45 minutes, depending on the required temperature, is a little slow but more energy efficient.
One of the standout features of the Eccotemp EM-2.5 is its exceptional energy efficiency of over 99%. This will help you save money on your heating bill.
7. Thermoflow UT10 – Best Value for Money
The Thermoflow UT10 under sink water heater has a 2.5 gallon capacity and is a good value product. It's easy to install and has a solid build quality, featuring a stainless steel, low-maintenance tank.
|Temperature Range||45°F – 167°F|
|Build quality||Stainless steel, low-maintenance tank|
|Safety features||Anti-freeze mode, maximum temperature of 167°F|
|Reheat time||May take a while to reheat if hot water runs out|
|Recommended use||Hand washing and teeth brushing|
The Thermoflow UT10 has a traditional, industrial design and a tapered top for easy access to the settings dial. It is not wall-mountable, but fits well in under-sink cabinets. Keep in mind that the power cord is only 30 inches long, so you'll need a nearby power source for installation.
To install the Thermoflow UT10, simply attach the water inflow and outflow and plug it into an outlet. This mini-tank heater has added safety features, including an anti-freeze mode for colder climates and a maximum temperature of 167°F.
The 2.5-gallon tank may take a while to reheat if you run out of hot water, so keep this in mind if you have a high hot water demand. However, it's a good choice for hand washing and teeth brushing.
Find Your Perfect On-Demand Hot Water Heater: A Comprehensive Buyer's Guide
Choosing the best under sink water heater for your home can be challenging. We've compiled everything you need to know to make an informed decision. Avoid feeling lukewarm about your purchase.
Size And Space
When choosing an under sink water heater, consider the size and space available for installation. Under sink heaters come in a range of shapes and sizes, from small tankless models to larger capacity tanks.
Before purchasing an under sink heater, assess the space where it will be installed. Wall-mounted under sink water heaters can be a space-saving option, as they allow for storage space below the heater itself. There is also an aesthetic consideration to make – small, tankless heaters may have less of an impact on the design of your bathroom and may blend seamlessly into the existing design (3).
Under sink water heaters provide a continuous flow of hot water, unlike tank-style heaters which can run out. A 2.5-gallon tank may not be sufficient for high-demand faucets and could run out in under 60 seconds. Therefore, the reheating power of a tank is important to consider.
Most under sink water heaters can regain heat in under 20 minutes. If you prefer very hot water, you may want to consider a higher-powered heater to reduce the reheating time.
Flow Rate (GPM)
Flow rate is important for faucets, just as it's for showerheads. We've all experienced disappointment with a faucet that produces a dribble. In our homes, we often invest in powerful faucets to increase flow.
Under sink tank heaters don't usually affect the flow rate of your faucet because the water is already heated and ready to be pumped through the pipes. A good benchmark for an under sink heater is a flow rate of 1.5 GPM (gallons per minute).
Under sink water heaters can range from 90-99.8% electricity efficiency and are often energy rated on a scale from A to F. Tankless heaters are generally more energy efficient and a good option for those looking to go green (4).
There are strong incentives for investing in under sink heaters for their energy efficiency. Consider looking for the most energy-efficient options available.
The standard voltage for electrical outlets in the United States is 120V, which is compatible with most under sink water heaters. However, some modern, high-powered tankless heaters may require an adaptor. It's important to ensure that your electrical outlets can handle the power of an under sink water heater.
Safety features, such as thermostats and freeze protection, can be worth investing in for under sink water heaters. Thermostats can shut off the heater if temperatures rise, and freeze protection can prevent damage to the heater during cold snaps.
Many under sink water heaters also offer a temperature/pressure (T/P) valve. If the T/P valve is not already integrated into the unit, it should be professionally installed to ensure the heater is safe to use.
Ease of Installation
Under sink water heaters often have the appeal of being easy to install. You simply need to connect the inflow to the cold water and the outflow to your faucets, and then plug it into a power outlet to have hot water flowing.
However, some models may be more complex and require either plumbing experience to set up the T/P valve correctly or an electrician to ensure compatibility with your home's power supply. If you're unsure, it's best to seek professional help.
Keep in mind that while some under sink water heaters are suitable for DIY installation, doing so may void the warranty. It's important to read the fine print carefully to understand the terms of any warranty, as a 5-year warranty may come with the requirement for professional installation.
It's important to consider the warranty when purchasing an under sink water heater. Even with thorough research, there is always a possibility of a factory defect or other issue. Having a warranty in place can provide peace of mind in the event of an issue. Many under sink water heaters come with a standard warranty of one or two years, but some brands offer extended warranties of up to five or six years, or even lifetime warranties in some cases.
Tank vs Tankless Water Heater
Under sink water heaters can come with a tank or be tankless. Tank-style water heaters have a capacity of 2.5 to 7 gallons, while tankless water heaters superheat water as it passes through a medium within the heater.
Tankless water heaters are available in gas or electric versions and are typically more expensive and technologically advanced than other types. They often feature digital displays and touch screens. Tankless water heaters are also known for their sleek, compact design, as they don't require a large storage tank. Wall-mounted versions can be placed anywhere in the home.
In terms of energy efficiency, tankless water heaters use up to 33% less energy than traditional tank water heaters, as they don't need to constantly heat and store hot water. This makes them a more energy-saving option (2).
Tank Or Point-of-Use (POU) Water Heaters
Traditional tank water heaters come in various sizes, but to fit under your sink, you may prefer the smaller 2.5 to 4 gallon options. These are sufficient for occasional use, such as washing your hands in the bathroom. However, if you have the hot water faucet running, even a 4-gallon tank can be emptied in a few minutes. The reheat time for a tank water heater can vary from 20 minutes to over an hour.
Point-of-use (POU) water heaters are typically easy to install and competitively priced, but there is a risk of running out of hot water.
There are various types of under sink water heaters available to fit different kitchen, bathroom, and garage needs. When selecting an under sink water heater, it's important to consider factors such as voltage and volume.
Under sink water heaters provide instant hot water at every sink in your home, eliminating the need to endure cold water while washing your hands or brushing your teeth. These water heaters are also efficient, saving money on energy bills and reducing water waste. It’s a win-win for your wallet and the planet.
So what are you waiting for? The perfect under sink water heater is out there, all you need to do is choose.